FRIENDSWOOD, Texas--(BUSINESS WIRE)--Castle Biosciences, Inc., a provider of molecular diagnostics to improve
cancer treatment decisions, today announced the publication of the first
prospective assessment of prognostic performance for the DecisionDx®-Melanoma
test in a multi-center population of patients with cutaneous (skin)
melanoma. The gene expression profile (GEP) test uses tumor biology to
provide an individual risk of recurrence in cutaneous melanoma patients.

The paper titled, “Interim Analysis of Survival in a Prospective,
Multi-center Registry Cohort of Cutaneous Melanoma Tested with a
Prognostic 31-Gene Expression Profile Test,” was recently published in
the Journal of Hematology & Oncology. In the study of 322
prospectively tested patients, the DecisionDx-Melanoma test demonstrated
a robust ability to predict recurrence, distant metastasis, and death at
year 3 of an anticipated 5-year prospective, multi-center registry study.

“Since two-thirds of all melanoma deaths occur in patients diagnosed
with early-stage disease, distinguishing patients with high-risk tumor
biology from those patients who are at a lower risk of recurrence is a
clinically important goal to drive appropriate management decisions,”
commented study co-investigator and senior author Kelly M. McMasters,
M.D., Ph.D., Chair of the Department of Surgery, University of
Louisville. “The strong association of test results with outcomes across
multiple practice settings in this prospective, multi-center study
aligns with results from previous studies using archived tumor samples
and provides assurance of the test’s prognostic value.”

Of the 322 Stage I-IV patients from 11 dermatologic and surgical centers
assessed in this analysis, 88% were Stage I or II and 74% had a sentinel
lymph node biopsy (SLNB). Endpoints of recurrence-free survival (RFS),
distant metastasis-free survival (DMFS) and overall survival (OS) were
assessed using Kaplan-Meier and Cox regression analyses. Median
follow-up time for this analysis was 1.5 years for event-free patients.

Key Study Findings

For all endpoints assessed, the DecisionDx-Melanoma test was the most
sensitive prognostic factor including SLNB.

A high-risk (Class 2) result identified 80% of patients who
experienced a recurrence compared to 40% for a positive SLNB
result.

Similarly, the GEP test identified 83% of those who had a distant
metastases compared to 50% for a positive SLNB result.

The GEP test also identified 73% of those who died compared to 9%
for SLNB positive (see table).

Outcomes and correlation with DecisionDx-Melanoma class and SLN
status:

Recurrence

(n=25)

Distant metastasis

(n=12)

Death

(n=11)

Class 1 (n=248)

5 (2%)

2 (0.4%)

3 (2%)

Class 2 (n=74)

20 (27%)

10 (14%)

8 (11%)

p-value

<0.0001

<0.0001

0.0001

SLN negative (n=286)

15 (5%)

6 (2%)

10 (3%)

SLN positive (n=36)

10 (28%)

6 (17%)

1 (3%)

p-value

<0.0001

<0.001

1

Consistent with prior studies, the DecisionDx-Melanoma test was
significantly associated with recurrence, distant metastasis, and
death due to melanoma (p<0.001 for all). Among patients with Stage I
or II disease (n=282), the GEP test was also significantly associated
with each endpoint analyzed.

Significantly different RFS was observed for patients with a Class 1
result (97%) compared to those with a Class 2 result (77%; p<0.0001).
Similarly, significantly different DMFS (99% versus 87%; p<0.0001) and
OS (99% versus 92%; p<0.0001) were observed among all patients in the
analysis.

Multivariate analysis demonstrated that DecisionDx-Melanoma class is
an independent predictor of RFS outcome, along with Breslow thickness
and mitotic rate (p<0.01).

High negative predictive values (NPV) of 98% for recurrence and 99%
for distant metastasis demonstrate that a Class 1 outcome was
associated with a low risk of metastasis during the study.

Results from this interim prospective analysis are comparable to
recently reported results from Castle’s cumulative retrospective
cohort (n=782). While the median non-event follow-up time of 1.5 years
in this prospective analysis is shorter than that reported in the
cumulative retrospective studies (6.9 years), comparable 1.5-year RFS
rates were observed in both studies (97% and 95% for Class 1; 77% and
67% for Class 2).

“The results from this prospective, multicenter study further support
the robust body of evidence demonstrating that the DecisionDx-Melanoma
test provides consistent, clinically meaningful results,” noted study
co-investigator Eddy C. Hsueh, M.D., Professor and Director, Division of
Surgical Oncology, St. Louis University Hospital. “These prospective
results show that the GEP test for melanoma, in combination with
standard clinicopathologic factors, can strengthen risk determination
and improve patient management.”

The DecisionDx-Melanoma test uses tumor biology to provide a prediction
of individual risk of melanoma recurrence beyond traditional factors.
Using tissue from the primary melanoma, the test measures the expression
of 31 genes. The test has been validated in three multicenter studies
that have included 690 patients and have demonstrated consistent
results. Performance has also been confirmed in three independent,
prospective studies including 510 patients. The consistent high
performance and accuracy demonstrated in these studies, which combined
have included 1200 patients, provides confidence in disease management
plans that incorporate DecisionDx-Melanoma test results. Clinical impact
has been demonstrated in a multicenter and single-center study showing
that test results add additional patient-specific prognostic information
to complement traditional staging tools. More information about the test
and disease can be found at www.SkinMelanoma.com.

About Castle Biosciences

Castle Biosciences is a molecular diagnostics company dedicated to
helping patients and their physicians make the best possible treatment
and follow-up care decisions based on the individual molecular signature
of their tumor. The Company currently offers tests for patients with
cutaneous melanoma (DecisionDx®-Melanoma; www.SkinMelanoma.com)
and uveal melanoma (DecisionDx®-UM and DecisionDx®-PRAME; www.MyUvealMelanoma.com),
with development programs in other underserved cancers. Castle
Biosciences is based in Friendswood, TX (Houston), and has laboratory
operations in Phoenix, AZ. More information can be found at www.CastleBiosciences.com.

DecisionDx-UM, DecisionDx-Melanoma and DecisionDx-PRAME are the
trademarks of Castle Biosciences, Inc. Any other trademarks are the
property of their respective owners.